Gnome developers have laid out plans to make Clocks a core application in future Gnome releases and there have been some impressive work on this app. Some screenshots:
This is the main widow where you can add clocks from different timezones:
And all together, world clocks will look like this:
Setting up alarm:
And the stopwatch
The developers are looking for help. If you have some free time, you can visit their GIT web here.